propane

[legend]

Hi,

i don't know where this belongs,so i tried here.

I have an adapter to transfer propane from a large(20 lb) bottle into the smaller size for lanterns and cookstoves etc.

i guess i dont know what i am doing wrong as it does not even begin to transfer propane;i have tried upside down,on its side,and straight up.

when i weigh the bottles(small) first and afterward i might gain an ounce.

this has to be a no brainer,but,the answer escapes me..

anyone know how this should be done?

thanks

[zxcvbob]

Put the small bottle in the freezer first. The big tank should be warm.

Turn the big tank upside-down if it's a normal tank, so you get LP out the valve instead of gas.

You still won't get a full bottle, but you can get it over half full pretty easily.

[legend]

Thank you!

i am putting all the little bottles in the freezer overnight,and will try tomorrow.

I knew i was missing something real basic!

[Charlie Sometimes]

Warm the 20 lb cylinder inside your house- as warm as safely possible, avoid over pressure venting!
Put your empty small cylinders in the refrigerator or freezer before you attempt transfer (outside, if that is colder! :grin:)
The greater the difference in temperatures the better.
The big cylinder gets turned upside down- you want liquid transfer, not just gas.

Do the transfer outside- no open fires, sparks, etc., in case you do get a leak. Which by the way, you should check for with a soap & water solution (heavier on the dish liquid than normal).

Hopefully, that will take care of it.
You won't get a "full" refill- results vary with environment and technique, etc.

Transfer propane at your own risk. :violin:

[oneokie]

My best success filling the small bottles has been to leave it connected overnight.

[heathydee]

Full bottle on top upside down . Empty bottle underneath right way up . Cracking both cylinder valves will allow the liquified gas to dribble through very slowly . If you crack the bleed valve on the empty bottle the pressure of the top bottle willl force the liquified gas through into the bottom bottle . Do it outside and don't open the bleed valve too much . A little gas will be lost through the bleed valve. Keep the spanner or screwdriver handy to close the bleed valve when it begins to spurt liquid gas . This is a sign the bottle is full . It only takes a few minutes this way. Don't smoke .

[jixxerbill]

i thought most all newer propane bottles have a tip over valve in them now?? so if u turn it upside down it closes off the flow even if the valve is fully open...actually if the knob on the valve is three sided or three spokes so to speak it is a tip over valve.....just a thought .....bill

[Charlie Sometimes]

20 lb "grill" tanks have the OPD (?) valve, but not on anything bigger, AFAIK.

[zxcvbob]

40 lb tanks also have OPD valves but bigger tanks don't -- but I don't *think* they prevent you from drawing liquid out of an upside-down tank.

[Hardcast416taylor]

The newer 20 lb. tanks have the OPD valve internally to stop gas flow in the tank from exiting thru the top valve should it fall over or be inverted upside down. I have one of those little gadgets to fill the lantern type tanks with also. You can get some gas into them by leaving the 20 lb. tank standing correctly. However it is only gas vapor you will be transfering and not the liquid propane.Robert

[Charlie Sometimes]

My 30 lb. tanks don't have the OPD- I get them filled and retested as shop welding tanks.

[jmh54738]

I no longer put the throw away tanks that I wish to fill into the freezer. About 15% of the small cylinders that I have treated this way result in leakers after they are filled. Some how the main valve sustains damage. They are still Ok to use if left screwed onto the appliance. I now suspend the tank being filled in an ice water bath where the threaded valve area is not subject to so great a thermal shock. After filling , I pour water right into the valve area to check for leaks. Five to ten minutes will transfer from 8 to 12 ounces into a 14 ounce cylinder, depending upon the temperature difference. Been filling these for 40 years.

[MarkW]

An OPD valve doeas not have any sort of "tip over" protection, so it is perfectly fine to turn a bottle upside down to fill another.

Now what they do have is an excess flow restrictor, where if it senses a large flow such as when a hose would break it shuts off the gas. The work around here is to just crack open the valve very slowly, so try doing that and seeing if it solves your issues..

Keep in mind that you'll never be able to get much more than equal percentages and pressures in both tanks, so if your 20 pounder is only 15% full you'll only be able to get about 15% into your one pound bottle. Occasionally I've wondered about cobbling up a small piston pump to boost the pressure to fill up bottles full, but then I realize that if I were to spend that same amount of time mowing lawns instead I'd probably be able to buy more new bottles than I'd ever fill with that contraption.

[Beagler]

I have the refill fitting and use a 20 or 40 pounders to refill the 1 pounders I put the leather gloves on and get just a little gas in the pounder. remove from the tank and rotate and purge the pounder with the fitting untill its all frosty and almost empty. I know it wastes a little gas but it will get the pounder FULL but make sure you leave a little air space for the liquid to vapor.

[Bret4207]

I've never had much trouble filling my small tanks from the 20lbs tank, OPD or no. Something to check is to make sure the fitting are clean. A little lint or anything in the tank or device parts will screw up the process.

BTW- when using an OPD tank with a big torch, like the pavers use, open the tank valve and let the pressures equalize for a couple minutes. Otherwise th eOPD shuts down the flow.

[zxcvbob]

Keep in mind that you'll never be able to get much more than equal percentages and pressures in both tanks, so if your 20 pounder is only 15% full you'll only be able to get about 15% into your one pound bottle.You would think that, but it's not true. The pressure in a LP tank remains almost constant as long as there is liquid in the tank. It only starts dropping after all the liquid is used up. (it also drops if the tank is cold)

[Beagler]

OPD Overfill Prevention Device All it is a float on the end of a brass rod inside your tank much like you toilet float that stops water flow. Have cleaned up and refitted many tanks since they started using OPD valves. When you invert the tank the float floats up to the top (bottom end of tank). Bret4207 is right about the little shut off in the valve. Was running my 1972 Onan Gen Set on a 40 pounder powering a moon bounce for my wedding and when the rental company can back to take it down they plugged a massive vacuum in to the gen set it peeked the governor drawing a bunch of propane all at once and tripping the shut off valve on the tank. It leaned out the fuel and wouldve burnt up the engine if I didn't shut it down right away. Lesson learned for me dont use an OPD tank to power my gen anymore

[Fredx10sen]

Some great information to know. Thanks

[legend]

Thank you all i am glad i asked.

[legend]

Due to you all giving advise i have filled 16 small bottles this afternoon,this was a great saveings to me,and,i thank you all for your help.


legend

[leftiye]

There's a relief valve on the little bottles. Turn the big bottle upside down, open fill valve on the big tank and depress the relief valve on the bottle until liquid propane comes out of it. Release relief valve, close valve from tank. WEAR GLOVES unless you like frostbite.

[Charlie Sometimes]

I no longer put the throw away tanks that I wish to fill into the freezer. About 15% of the small cylinders that I have treated this way result in leakers after they are filled. Some how the main valve sustains damage. They are still Ok to use if left screwed onto the appliance. I now suspend the tank being filled in an ice water bath where the threaded valve area is not subject to so great a thermal shock. After filling , I pour water right into the valve area to check for leaks. Five to ten minutes will transfer from 8 to 12 ounces into a 14 ounce cylinder, depending upon the temperature difference. Been filling these for 40 years.

Cold water bath makes better sense- I would venture to say that the seals get too cold in the small cylinders when frozen and leak until they become pliable at warmer temps. I have had that issue this winter with the seals in the valve on a hand torch this year- slow to close off the pressure when turned off, and starting to leak off on an older one, because of the cold shop.

[PatMarlin]

Interesting info here. I setup a fill valve from my 500 gallon tank. Seems like the last ones I refilled, the little buggars would always leak out in the boat so I quit doing it.

[klcarroll]

Propane, like CO2 and Nitrous Oxide, is a gas that is stored in a liquid state inside a pressurized vessel. The pressure inside that closed vessel will stabilize at an EQUALIBRIUM PRESSURE that is related to both the material and the ambient temperature.

At 80 degrees Fahrenheit, a propane cylinder that has come to equilibrium will show you 128 psi. At 130 degrees that pressure will have doubled! The temperature is a controlling factor here!

ALL gases stored in a Liquid state have a unique physical characteristic that is referred to as their CRITICAL TEMPERATURE: .....Simply put, when the liquid gas in question reaches that temperature, NO amount of pressure will make it continue to behave as a liquid! ........It becomes a dense, high pressure gas that is called a "Supercritical Fluid". When this occurs, there is a dramatic pressure increase, and the same tank that was showing you 128 psi at 80 degrees may now be showing you 750 psi!!!

The Critical Temperature for Propane is 205 degrees Fahrenheit.

Because of the obvious dangers, the DOT requires that any pressure container for liquid stored gas have a "reserve volume" to allow for expansion. This reserve must NEVER be compromised! This is why ALL liquid stored gas containments have their capacity rated in pounds. If the refill technician determines a valid tare weight for the container, and never dispenses more than the rated number of pounds or ounces, a safe refill is the result. ........Any departure from that procedure, and he is building bombs.

If you are refilling small propane bottles without paying RELIGIOUS attention to a good quality scale, you are playing Russian Roulette!!


Kent

[PatMarlin]

Always amazed at the knowledge base here at CB. Great info KLC.

We have a 500 gal propane tank, and the fuel gage started leaking at it's housing block. Propane company wanted several hundred dollars to transfer the gas, and fix it. I had paid a them good money to re-valve it a few years ago, but the idiot did not change the gage housing, or even put a new gasket on it because it was an old model. Didn't even bother to tell me neither.

But the company sold, changed hands and I was stuck. They told me there was no other way to fix the problem.

I took a 2" PVC schedule 80 fem threaded coupler and turned the ID on one end to fit over the gage housing. Cleaned up the area to bare metal with a die grinder and JB welded it to the tank. Then capped it with a 2" male plug.

Shazamm- repaired with no leaks. Yes, I have to remove the plug to read the gage, once a year.

They called to schedule a repair and I told em' to stuff it.

[PatMarlin]

Pat, your lucky . . . leaking gas and grinders don't usually go well together . . . hopefully you tank is in the shade as the temp rises so will the pressure . . . did you try to tighten the four screws? Don't break them or you will be even more unhappy!

It was a very slight leak. Carbide die grinder bit- slow speed, their ain't no sparks. I should have clarified that.

Folks- what ever I do, don't try it at home ...:mrgreen:

I once knew a guy who checked for leaks on his propane tank with a match. No kiddin'. It doesn't ignite the tank.

[mazo kid]

I am able to get 12-14+ ounces of fill in the one pound tanks. The directions on my adapter say not to heat the larger tank over 85 degrees and to put the small tank in the freezer for 15-20 minutes. Then after connecting the 2 tanks, shut the large tank off after one minute. This worked for me.

[nanuk]

I use the relief valve on the 1lber.

I connect them, turn the filler upside down so the 1lber is horizontal and the relief valve is in the uppoer position, open the valve, pull the relief valve and when she starts spitting liquid, I close the relief valve, shut off the main tank and decouple.

I'm making up an extension so I can hold the 1lbers in the proper position for easier filling.

doing it this way, there is aways a "Head" in the 1lber to allow for expansion.

[Crusty Deary Ol'Coot]

Another possibility for refilling small tanks is buying small tanks made to be refilled.

I have two of these, not sure where my father-in-law bought them, but they have a mechanical bleed valve much like that found on bigger tanks. Take a wrench and open it up, fill the small tank until liquid comes out of the valve opening and then close it.

Trying to open the bleed valves on the small "non-refillable" tanks may or may not work as frost/ice may build up in the valve during filling, which then allows all of the gass in the small tank to bleed off.

Not so with those made for refilling, as there is a mechanical "seat" which seals excaping gas.

The Father-in-law was a sheet metal mechanic, so likely he bought the tanks at a supplier of such tools.

Keep em coming!

Crusty Deary Ol'Coot

[thebigmac]

[smilie=s:THANKS A LOT FOR ALL THIS INFORMATION. I THINK IT'S MIGHTY THOUGHTFUL OF ALL YOU MEMBERS TO CONTRIBUTE YOUR KNOWLEDGE TO OTHERS HERE. THIS IS WHAT MAKES "CAST BOOLITS" A GREAT PLACE TO SPEND YOUR TIME. bigmac

[Taylor]

I'm glad someone posted this.I couldn't make my refill gadget work either.Thanks.